Electro-fermentation (EF) circumvents the thermochemical limitation of conventional anaerobic fermentation technology by combining electrochemical and biological operations to form a bioelectrochemical system (BES). Shewanella oneidensis MR-1 is a model organism for researching BES in an anodic chamber of microbial fuel cells (MFCs)/microbial electrolytic cell (MECs), because of its genetic accessibility, respiratory versatility, and annotated genome sequence as well as in EF it does extracellular electron transfer (EET) both direct and indirectly, using many organic and inorganic substrates, such as oxygen, thiosulphate, fumarate, nitrate, nitrite, dimethyl sulfoxide (DMSO), elemental sulfur, etc. OmcA, CymA, MtrA, MtrB, MtrC, and CymA are primary proteins involved in the EET pathway, also known as Mtr pathway. Metabolically Shewanella oneidensis MR-1 has more tendency to utilize low molecular weight substrates such as amino acid, lactate, and pyruvate rather than glucose. EF Shewanella forms biofilm with the help of some auto aggregation elements such as type IV pili, curli protein, fimbriae, and surface adhesins on the surface of the electrode in MFC/MEC. Dozens of genetic methods are available to modify the genetic material of MR-1 including overexpression of adenyl cyclase, flavin synthesis pathway, MtrB gene enhancement, and multiple gene modifications for improvement of the EET pathway. Genetic modification has unlatched new paths in the field of commercial production of valuable products from MR-1 using EF. However, precaution is necessary since the long-term impacts of genetically engineered organisms on the environment and human health are yet unclear.